Pocket Gopher Mounds and Tunnels
Pocket gophers depend on their underground burrow (tunnel) systems to provide a protective place to nest, raise young, store food and locate sources of food. The soil that is excavated in the process of digging the underground tunnels is deposited at the entrance of the tunnel and becomes the gopher mound.
Pocket gopher mounds are horseshoe-like, irregular or crescent- shaped with a hole leading to the sub-surface portion of the burrow system. The shape of the gopher hole is crescent-like or irregularly-shaped because the gopher pushes soil from the underground tunnels to the ground surface at an angle which results in a hole that is not round. Another characteristic of the mound is the presence of a soil plug in the gopher hole. Using their nose and front teeth, pocket gophers create an earth plug to close their in the tunnel.
Burrow systems are made up of main tunnels, lateral tunnels and deep tunnels. The main tunnel is usually less than two feet below ground, parallel to the ground and ends at the mound. The main tunnel’s depth depends on soil conditions. The drier the soil, the deeper the tunnels.
The lateral tunnels branch off the main tunnel and are used in foraging for food below ground. Gophers will also construct lateral burrows or feeding tunnels that end at the ground surface with a small mound and an area of vegetation cleared around the mound. A soil plug closes any opening to the tunnels, an important part of the burrow system since it helps reduce the likelihood of a predator entering the tunnels. If there is a question of whether a tunnel system is active, just dig open a mound or tunnel. The hole will be plugged in a day or two if a pocket gopher is living in the tunnel.
The deep branching tunnels also come off the main tunnel and are used as nesting, sleeping, and waste storage and food storage sites. The maximum depth of some of the deep chambers may be as much as six feet below the ground.
Tunnel diameter will be about three inches, but will vary with the size of the adult stage of the gopher. In general, the burrow of a male gopher has fewer branches than the burrow of females. Pocket gophers dig out tunnels even when there is snow on the ground because they don’t hibernate. The gopher will make what is called a mud cast under the snow cover. After the snow melts, the mud casts are seen radiating out from the tunnel openings on the ground surface.